What is Agatha best novel?

The Murder of Roger Ackroyd (1926) is widely regarded as Agatha Christie's best novel by many readers and critics alike. The novel is notable for its innovative and groundbreaking use of the unreliable narrator technique, which adds a layer of complexity and intrigue to the story. The plot revolves around the murder of Roger Ackroyd, the wealthy owner of Fernly Park. The main character, Dr. Sheppard, investigates the crime and finds himself entangled in a web of deceit and suspicion. The novel's clever construction and unexpected twist ending make it a classic and often considered the pinnacle of Christie's writing.